short followup: Unfortunatly all missions are bugged now. Tried different missions and types with different planes. Gamebreaker with error code 308-400-00209 !
Wild guess: Maybe it has something to to with the reputation system. In a previous flight I got a B or A rating, but my overall status got an upgrade to max S. May the system get’s confused for (in-flight) penalties/bonuses while the total rep is in an overflow.
Edit: the assumption could be correct. After having a deliberately really bad flight with one of the employee missions my rep was tanked and afterwards I was able to do a formaly unplayable mission. Why own and employee planes could be treated differently… well it doent make sense to me…